Electric car signaling system.



J. W. TATUM.

ELECTRIC CAB SIGNALING SYSTEM.

APYLIGATION TILED MAR. 15, 1911.

Patented July 8, 1913.

2 SHEETS-SHEET 1.

J. W. TATUM.

ELECTRIC GAB SIGNALING SYSTEM.

APPLICATION IILED MARJS, 1911.

1,066,681 Patented July 8,1913.

F 2 SHEETS-SHEET 2.

. UNITED STATESZATENT OFFICE.

JAMES W. TATUM, OF ANGIER, NORTH CAROLINA, ASSIGNOR OF ONE-SIXTH TO B.N. DUKE AND ONE-SIXTH TO W. FULLER .'0F NEW YORK, N. Y., AND ONE-SIXTHT0 E. J'. PARRISH, ONE-SIXTH TO JOHN W. SMITH, AND ONE-SIXTH TO ROBERTB.

BOONE, OF DURHAM, NORTH CAROLINA.

ELECTRIC CAB SIGNALING SYSTEM.

Specification of Letters Patent.

Patented July 8, 1913.

To all whom it may concern:

Be it known that I, James W. Tn'ru'iu, a citizen of the United States,residing at Angler, in the county of I-larnctt and State of NorthCarolina, have invented new and useful Improvements in Electric CabSignaling Systems, of which the following is a specification.

My invention relates to cab signaling systems for railways, andparticularly to such systems for steam railroads. While my invention isof the relation specified, however,

it will be readily apparent upon an understanding of it that t e systemmay be used in other connections, and that one or more of its featuresmay be used in the same or other connections.

In my Patent No. 815,131, March 13, 1906, I have disclosed a signalingsystem in which use is made of a telephone in a car or cab, and inconnection through suitable contacts With conductors which extend alongthe roadway, one of the conductors, in this patent being the rails, andthe other of the conductors being a trolley suitably sup ported alongthe track. An audible alarm in the form of a bell is included in thecircuit between the conductors, but separate from the tele hone in sucha manner that when two trains approach within a certain distance of eachother, the alarm is sounded by the passage of a current of a certainstrength over the circuit. A shunt line in cluding the telephonetransmitter and the receiver, and in which there are contacts controlledby the movement of the receiver hook upon the removal .of the receiver,is provided for the par ose of short circuiting or shunting the audiblealarm or electric bell when it is desired to transmit messages by thetelephone. Normally this shunt line is opened, but upon the removal, ofthe re ceiver from the hook the shunt line about the bell is closed, andmessages may be transmitted without interference from the electric bell.

-The apparatus of the system of my present invention, diifers in severalparticular features, from the apparatus of my prior atent referred toabove. Chief among these differences is the use of an intermittent orpulsatory current for the operation of the warning signals .or alarmsfor trains running in the same direction. A particular device, and aparticularly arranged circuit are provided for the transmitting orsending of this intermittent or pulsatory current to give the warningsignal upon the approach of two trains within a dangerous distance ofeach other. Particular means are also provided for rendering this meansfor transmitting the intermittent or pulsatory current inoperative, andrendering the tele )hone operative for the transmission of into ligencesbetween trains running in the same direction.

The object of my invention is to produce the simplest system possiblefor trains running in the same direction which will give etliciontresults, and these several features of my invention have been designedand organizedtogether to the procurement of the best possibleaccomplishment of the objects of my invention.

The contacts which I prefer to use in the embodiment of my inventionwhich I shall describe, are made of substantial proportions, and areoperated from a source of power of relatively large size. The contactsmay therefore be readily kept clean, and owing to the large power fromwhich they are actuated are not subject to the same troubles as smallcontacts are subject to under the same conditions. Poor contact andsticking of contacts are most effectually avoided by this provision. Ina fourth place sticking of )arts of the a paratus is etlcctually avoidedby the use of the intermittent or pulsatory current.

In the accompanying drawings I disclose a specific embodiment of myinvention.

Figure 1 is a diagrammatic drawing of my invention, showing two railwaycars, or the cabs of two locomotives equipped with the apparatus of thesystem of my invention, and in which conductors other than the rails ofthe tracks are used for the transmission of signals; Fig. 2 is a similardiagrammatic drawing in which the rails of the track are used as a partof the circuits of the system; and Fig. 3 is a diagrammatic drawing ofthe circuits of the standard telephone generally used in telephonepractice today.

Referring to the drawing 10, 10 are the rails of a track.

11 and 12 represent two cars or trains at a distance from each other.Each car is equipped with a telephone 13 of the construction shown inFig. 3. This telephone includes a bell 14 and a transmitter 15, the bellbeing of the type usually used for calling. It will be noted that thebell is cut out of circuit when the receiver is raised from its hook,and that the transmitter 15 is placed in circuit for talking. Also oneach car is a mechanical vibrator 16 consisting of an eccentric 17 on anaxle of the car and connecting links 18 and 19 which operate a lever 20carrying a relatively large contact 21. The lever 20 is pivoted at acentral point and is oscillated back and forth by the movement of theeccentric on the axle to make and break contact with a relatively broadcooperating spring contact 22. These contacts 21 and 22 are normallyconnected in series with the telephone through a source of power 23between them and the telephone.

Conductors 24and 25 are laid along the track, and are engaged bytrolleys 26 and 27 from the telephones, the'arrangcment of the trolleyswith respect to the conductors being such that a series circuit isformed from train 11 to train 12 as follows: train 11, telephone 13,source of power 23, con

tacts 22 and 21, trolley 27, conductor 25,

trolley 27 of train 12, contacts 21 and 22,

. trolley 26, conductor 24, trolley 26 of train 11, and back totelephone 13 of train 11. A short circuiting switch is provided in connection with each air of contacts 21 and 22, and which normally is inthe open circuit position shown.

With the system installed as described, the operation is as follows:When. two trains or cars approach within a certain distanceot eachother,this distance being determined by the resistance of the lineconductors 24 and 25, and the resistance of the apparatus, anintermittent or pulsatory current is sent over the series circuit justdescribed, from the sources of power 23 through the action of themechanical vibrators 16. The time intervals of the impulses of thiscurrent are dependent upon the relative speeds of the two trains, andthey may or may not be regular, depending upon those speeds, but theywill be of such frequency as to give rapid operation of the warningsignal which in this embodiment is the telephone bell. Having receivedthis signal, an engineer or other operator in the-one train may closethe short circuit switch 28 on his train and thus short circuit thecontacts 21 and 22, with the result'that the vibrator is cut out ofcircuit and the bell stops ringing, upon the removal of the receiverfrom the hook. This change of circuit connections and the apparatus inthe one train, say .train-11, makes a change in the regularity in thecurrent impulses transmitted through the circuit, inasmuch as only onevibrator is now afl'ecting the circuit, whereas before the change wasmade, both vibrators were acting. The engineer in the other traintherefore knows that the engineer ofan adjacent train wishes to talk tohim. He thereforecloses his. switch 28 to short circuit the contacts 21and 22 of his train, and removes the receiver of his telephone from thehook, whereupon the engineers of the two trams:

- concerning the movements of the two trains,

the receivers may again be placed upon the hooks and the shortcircuiting switches opened, whereupon the warning signal will continuedto sound until one or the other of the trains is.removedfrom thesignaling distance of-the other. By the use of this system, which issimple in extreme, and

which is most reliable, collisions. between trains running in the samedirection may be avoided. Furthermore the system has the advantagepresent with most telephone communicating systems between trains orcabs, of furnishing a ready means of communication by which theengineers of the-trains may be accurately informed as to the everymovlement of other trains in their section of trac I In Fig. 2 I haveshown a modification of previously described, and need not be fur thercommented upon. The mechanical vibrator, however, instead of beingactuated 1 from an eccentric on an axle, is actuated b an eccentric on acountershaft 29 in the ca of the locomotive, an eccentric or crank 31being provided on the shaft for actuating the contacts 21 and 22, andthe shaft being.

belted to an axle of the locomotive. It-is to be noted that the beltgearing between the shaft or axle of the locomotive and the shaft 29 isa step-up gearing, such that the shaft 29 is driven at a much higherrate of speed than the axle. This gives a most eificient actuation ofthe warning signal even at low speeds of the locomotive. Otherwise thesystem of Fig. 2 is the same as the'system of Fi 1.

an. I have described the best form of my invention now known tome, myinvent-ion is capable of many modifications without departing in anywisefrom its generic s' irit. Likewise one or more of the features Lo myinvention may be used in systems of phone receiver-hook switch the samecharacter, or in systems of other characters.- so also some of itsfeatures may be changed in some degree without departing from itsgeneric spirit. For instance the pulsating current may not beintermittent and may not be attained by a mechanical vibrator, one ormore of the well known electrical vibrators being used. So also 1 mayassociate the short circuiting switches with the hook of the telephonereceiver, as in my prior patent referred to. I desire to cover all suchmodifications in the annexed claims.

hat I claim is 1. in a signaling device, an electric circuit including ahell, it teletphone, a teleor alternately cutt-ing out the bell and thetelephone from the circuit, anexciter in the circuit, a spring contact,a vibrating contact movable toward and from the spring contact andadapted to make and break the circuit, a second telephone, a secondvibrating contact, conductors leading from the first telephone and thefirst vi brnngig contact to the second telephone and second vibratingcontact, and a shunt switch located between the telephone and theconductor leading from the vibrating contact and adapted to shunt theexciter and the contacts from the circuit.

2. In a signaling device, and in combination, movable members,conductors station ary relative to the movable members, a circuit uponeach member being closed througL said conductors, said circuit includinga telephone, a bell, means for alternately cutting said telephone andbell out of the circuit, an exciter, a spring contact, and a pivotedcontact adapted for movement toward and from the spring contact, meanscarried upon each member for engagement with the respective movablecontacts for vibrating the same whereby to open and close the circuit ofeach member, and shunt switches located between the telephones and themovable contacts whereby the exciters and the contacts may be shuntedfrom .the circuit through the stationary conductors.

In testimony whereof I have hereunto set my hand in presence of twosubscribing wiitnesses.

JAMES "W. TATUM.

Witnesses J. W. I)UNN'ING, J P. 1)ARRISIL

